1. Technical Field
The present invention relates to detection device, a sensor device, and an electronic apparatus or the like.
2. Related Art
A conventional infrared detection device is known which uses a pyroelectric element. A human body, for example, radiates infrared rays having a wavelength in the vicinity of 10 μm, and by detecting the infrared rays, the presence or temperature information of a human body can be detected without contact. Consequently, such an infrared detection circuit can be used to detect an intruder or measure a physical quantity.
The technique disclosed in Japanese Laid-Open Patent Application Publication No. 59-142427, for example, is known as a conventional technique for an infrared detection device. In the conventional technique disclosed in this publication, a chopper is used to vary the temperature of a pyroelectric element to generate a pyroelectric current while switching between irradiation and blocking of infrared rays to the pyroelectric element, and this pyroelectric current is charged into the pyroelectric element as such and thereby detected as a voltage signal.
However, since the relative permittivity of the ferroelectric body used in the pyroelectric element is extremely high in this conventional technique, the electrical capacitance of the pyroelectric element is necessarily large, and a large voltage signal cannot be retrieved. As a result, it is difficult to increase the sensitivity of the detection device.